From what I can see, you are changing the player's simultaneously on a given row and column:

                       if (playerPositionRow < 0 || matrixChamber[playerPositionRow][playerPositionCol] == 0){
                            playerPositionRow = playerPositionRow + 1;
                            playerPositionCol = playerPositionCol + 1;

When comparing with another solution that has been refactored by MartinBG, you will see a different placement validation:

           if (hsChamber[startPlRow][startPlCol]) {
                if (isRowValid(hsChamber, startPlRow - 1) && !hsChamber[startPlRow - 1][startPlCol]) {
                    startPlRow--; // move up
                } else if (isColValid(hsChamber, startPlCol + 1) && !hsChamber[startPlRow][startPlCol + 1]) {
                    startPlCol++; // move right
                } else if (isRowValid(hsChamber, startPlRow + 1) && !hsChamber[startPlRow + 1][startPlCol]) {
                    startPlRow++; // move down
                } else if (isColValid(hsChamber, startPlCol - 1) && !hsChamber[startPlRow][startPlCol - 1]) {
                    startPlCol--; // move left
                }

I would strongly advise to compare the whole solution with yours and to rewrite it, most importantly to cut down on those mega if-validations, where you easily can get lost.

Best,

import java.util.Scanner;
 
public class Pr08TheHeiganDance {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
 
        double hsPoints = 3000000.0;
        int playerPoints = 18500;
 
        int startPlRow = 7;
        int startPlCol = 7;
 
        String lastSpell = "";
        boolean activeCloud = false;
 
        double damage = Double.parseDouble(scanner.nextLine());
 
        while (playerPoints > 0 && hsPoints > 0) {
            hsPoints -= damage;
            
            if (activeCloud) {
                playerPoints -= 3500;
                activeCloud = false;
                
                if (playerPoints < 0) {
                    break;
                }
            }
            
            if (hsPoints < 0) {
                break;
            }
            
            String[] tokens = scanner.nextLine().split("\\s+");
 
            String spell = tokens[0];
            int row = Integer.parseInt(tokens[1]);
            int col = Integer.parseInt(tokens[2]);
 
            boolean[][] hsChamber = new boolean[15][15];
            for (int i = row - 1; i <= row + 1; i++) {
                if (i >= 0 && i < hsChamber.length) {
                    for (int j = col - 1; j <= col + 1; j++) {
                        if (j >= 0 && j < hsChamber[row].length) {
                            hsChamber[i][j] = true;
                        }
                    }
                }
            }
 
            if (hsChamber[startPlRow][startPlCol]) {
                if (isRowValid(hsChamber, startPlRow - 1) && !hsChamber[startPlRow - 1][startPlCol]) {
                    startPlRow--; // move up
                } else if (isColValid(hsChamber, startPlCol + 1) && !hsChamber[startPlRow][startPlCol + 1]) {
                    startPlCol++; // move right
                } else if (isRowValid(hsChamber, startPlRow + 1) && !hsChamber[startPlRow + 1][startPlCol]) {
                    startPlRow++; // move down
                } else if (isColValid(hsChamber, startPlCol - 1) && !hsChamber[startPlRow][startPlCol - 1]) {
                    startPlCol--; // move left
                }
 
                if (hsChamber[startPlRow][startPlCol]) {
                    switch (spell) {
                    case "Cloud":
                        playerPoints -= 3500;
                        activeCloud = true;
                        lastSpell = "Plague Cloud";
                        break;
                    case "Eruption":
                        playerPoints -= 6000;
                        lastSpell = spell;
                        break;
                    default:
                        throw new IllegalArgumentException("Invalid spell: " + spell);
                    }
                }
            }
        }
 
        if (hsPoints > 0) {
            System.out.printf("Heigan: %.2f%n", hsPoints);
        } else {
            System.out.println("Heigan: Defeated!");
        }
        if (playerPoints > 0) {
            System.out.printf("Player: %d%n", playerPoints);
        } else {
            System.out.println("Player: Killed by " + lastSpell);
        }
 
        System.out.println("Final position: " + startPlRow + ", " + startPlCol);
    }
 
    private static boolean isRowValid(boolean[][] hsChamber, int startPlRow) {
        return startPlRow >= 0 && startPlRow < hsChamber[startPlRow].length;
    }
 
    private static boolean isColValid(boolean[][] hsChamber, int startPlCol) {
        return startPlCol >= 0 && startPlCol < hsChamber.length;
    }
}