It seems unlikely that you can "scare the seller into pulling out of their current deal". If they have an accepted offer and the contingencies are fulfilled in a timely fashion, neither party can unilaterally pull out.
If there is an accepted offer you can write the offer and get it accepted in secondary position. There are a couple of ways that you may be moved from secondary to primary position.
First, if the first offer has a "bump" clause, a home sale contingency clause, in their offer. The seller can "bump" the first offer with a notice to remove the home sale contingency and move it forward. If the buyer can not remove it and move forward then they will notify you about moving into primary.
If the first offer doesn't have this as a contingency, the only way for you to be moved into primary is if the buyer and seller mutually agree to part ways. Sometimes this is due to inspection issues and sometimes it is due to financing.
It doesn't hurt you to be in secondary and you never know. The worst case scenario is that you don't get the home. If you find another home during this offer sitting in secondary, you can simply remove yourself from being in secondary on the first home with a notice to withdraw.
Good luck! If you have any further questions about this you can post more or you can email me directly.
Have a good day!