As per AIIMS MBBS cutoff 2019, candidates belonging to General category will be required to score at least 50% marks in AIIMS MBBS entrance exam, while those belonging to OBC category need to score at least 45% and SC/ST candidates will be required to score at least 40% in order to qualify the exam. 

The merit rank is 53.

Since the scores are not revealed on the results, the cut-offs for AIIMS are given in ranks or percentile only.

Here's a link that'll help you with the cut-offs for all the centres of AIIMS

Https://www.google.com/amp/s/medicine.careers360.com/articles/aiims-mbbs-cut-off/amp

No, 4000 is not at all a safe rank.