When a user is trying to book a room, another user is able to "steal" the room if they complete their booking quicker. Once a booking is in the process of being made, another user should not be able to make a booking in the same room if the times overlapped. Similar to online ticket websites that hold tickets for a set period of time (usually 10 minutes) to allow you time to complete the transaction. So for bookings, once the user has selected the available booking, the slot should be held for a set period of time or released once the time expires.