Having an implant in your body and trying to use the Proxmark3 can be a tricky balancing act of trying to hold the Proxmark3 antenna just so over your implant and then trying to hit Enter to initiate the command. But, there is a way to solve this by using the msleep command along with command chaining to add a delay between pressing enter and the command you want to execute against your implant is actually run. For example, to perform an lf search with a 3 second delay before actually performing the search, you would use something like this;
msleep -t 3000; lf search
So basically you issue the msleep command first (in milliseconds) then use a semicolon to chain the next command to execute after msleep.