This is how I read it. The underwriters have a call option. They've got the challenge of selling 2.7M stock. If they can trade in such a way as not to drive down the price of the, but allow it to climb as much as possible, then the call option is their reward. This motivates the underwriter's traders to fetch the highest price possible for the shares offered.
I'm not sure that this create a special opportunity to buy 30 day call options. It seems pretty hard to push the price up while selling 2.7M shares.
Also it might seem the underwriter's call option would motivate analysts at GS and MS not to talk the stock down. In law, there is supposed to be a wall of separation between the traders and analysts at GS and MS. So in principle, the analysts are independent. Even so, it's probably prudent for these analysts not to say anything good or bad while this call is in play.
If this is like most IPOs or Follow-Ons the underwriters have an optional over allotment used to stabilize the market post offering. These are actual shares, not an option. If they are sold Tesla receives the proceeds minus the underwriter's commission. Higher the price, the more money for everyone - but, and this is real, - the underwriter's first desire is to keep the stock above the original offering price for a reasonable amount of time. So what happens is that the underwriters can also buy shares on the open market to support the stock. If they do so they can sell them later and not exercise the overallotment. It all depends on the market.
The reason why the underwriter may not just want to sell the overallotment is that the large institutional clients that the underwriter sold the initial follow-on shares to may not be happy if the sales drives the price lower. Remember that these are very big banks selling to very big fund. If the bank behaves badly it doesn't take much for the fund to tell them to screw off next time, which makes the traders at the bank (who have an active role in IPOs & follow-ons) and investment banker's bosses very, very unhappy.