diff --git a/runtime/include/panic.h b/runtime/include/panic.h
index 509a45f..d973c4b 100644
--- a/runtime/include/panic.h
+++ b/runtime/include/panic.h
@@ -4,7 +4,7 @@
 #include <stdarg.h>
 #include <stdlib.h>
 
-__attribute__((noreturn)) static inline void
+__attribute__((noreturn, format(printf, 1, 2))) static inline void
 panic(const char *format, ...)
 {
 	va_list args;
diff --git a/runtime/src/sandbox.c b/runtime/src/sandbox.c
index e056fed..1aec382 100644
--- a/runtime/src/sandbox.c
+++ b/runtime/src/sandbox.c
@@ -441,7 +441,7 @@ sandbox_free(struct sandbox *sandbox)
 	errno = 0;
 	rc    = munmap(stkaddr, stksz);
 	if (rc == -1) {
-		error_message = "Failed to unmap stack";
+		fprintf(stderr, "Thread %lu | Failed to unmap stack %p\n", pthread_self(), sandbox);
 		goto err_free_stack_failed;
 	};
 
@@ -455,7 +455,7 @@ sandbox_free(struct sandbox *sandbox)
 	errno = 0;
 	rc    = munmap(sandbox, sandbox_address_space_size);
 	if (rc == -1) {
-		error_message = "Failed to unmap sandbox";
+		fprintf(stderr, "Thread %lu | Failed to unmap sanbox %p\n", pthread_self(), sandbox);
 		goto err_free_sandbox_failed;
 	};
 
@@ -465,5 +465,5 @@ err_free_sandbox_failed:
 err_free_stack_failed:
 err:
 	/* Errors freeing memory is a fatal error */
-	panic(error_message);
+	panic("Thread %lu | Failed to free sandbox %p\n", pthread_self(), sandbox);
 }