Well, yes. After he presented an acquisition agreement to the Twitter board of directors and presented them with a committed financing package, the Twitter board literally could not refuse Musk’s without spending the rest of their lives in depositions with Twitter public shareholders.
So Twitter of course accepted the deal, Musk (voluntarily) signed the merger agreement, and that was that - he was indeed locked into buying the company (subject to certain conditions - receipt of regulatory approvals, Twitter shareholders approving the merger, stuff like that).
This was not like hitting a lucky streak at the craps table and waking up 12 hours later with a new wife. The decision to purchase was deliberate. Doesn’t mean he didn’t develop buyer’s remorse after - he most certainly did - but the threatened tender offer, the rich, target-friendly merger agreement - this is exactly how you aggressively and deliberately pursue ownership of a big public company.