iPhone randomly reboots into safe mode when opening apps
If you mean MobileSubstrate SafeMode…

Since it has happened multiple times, restarting hasn't seemed to fix it. Consequently, I would recommend performing the following:


Remove recently installed extensions.

If you know that you recently installed a Cydia package, or updated one, I would suggest uninstalling that package and see if it makes a difference.
Use Crash Reporter.

Crash Reporter will attempt to guess the cause of a crash. After installing, next time your iPhone crashes, you can check the 'Possible Causes' list in Crash Reporter for its guess on the cause. You can then try to delete the package in Cydia and see if that fixes the problem.