diff --git a/stm-firmware/safety/safety-controller.c b/stm-firmware/safety/safety-controller.c
index be99209..1bdbea4 100644
--- a/stm-firmware/safety/safety-controller.c
+++ b/stm-firmware/safety/safety-controller.c
@@ -30,6 +30,8 @@
 #include <reflow-controller/stack-check.h>
 #include <helper-macros/helper-macros.h>
 #include <reflow-controller/systick.h>
+#include <stm32/stm32f4xx.h>
+#include <cmsis/core_cm4.h>
 #include <stddef.h>
 #include <string.h>
 
@@ -148,11 +150,15 @@ static void safety_controller_process_active_timing_mons()
 {
 	uint32_t i;
 	volatile struct timing_mon *current_mon;
+	uint64_t last;
 
 	for (i = 0; i < COUNT_OF(timings); i++) {
 		current_mon = &timings[i];
 		if (current_mon->enabled) {
-			if (systick_ticks_have_passed(current_mon->last, current_mon->max_delta))
+			__disable_irq();
+			last = current_mon->last;
+			__enable_irq();
+			if (systick_ticks_have_passed(last, current_mon->max_delta))
 				safety_controller_report_error(current_mon->associated_flag);
 		}
 	}
@@ -164,12 +170,9 @@ static void safety_controller_process_checks()
 	enum analog_monitor_status amon_state;
 	float amon_value;
 
-
-
 	if (!startup_completed && systick_get_global_tick() >= 1000)
 		startup_completed = true;
 
-
 	if (startup_completed) {
 		amon_state = safety_controller_get_analog_mon_value(ERR_AMON_VREF, &amon_value);
 		if (amon_state != ANALOG_MONITOR_OK)
@@ -181,7 +184,6 @@ static void safety_controller_process_checks()
 	}
 
 	safety_controller_process_active_timing_mons();
-
 }
 
 int safety_controller_report_error(enum safety_flag flag)