If the undershoot is flat you can duck under to get extra distance. Not everyone's cup of tea, but if you're close to the margain...
The very fact that you feel that the approch requires something which is not done is a message that you shouldn't be landing there. Short runway, limit tail wind which could easily go over the limit, heavy rain can make the braking action poorer than imagined and control of flight path difficult these are too many variables which can prevent a successful outcome. Not a safe decision to continue the landing.